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Proceedings Paper

Analysis of deprotection reaction for chemically amplified resists by using FT-IR spectrometer with exposure tool
Author(s): Yasuhiro Miyake; Mariko Isono; Atsushi Sekiguchi
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Paper Abstract

A Fourier transform infrared (FT-IR) spectrometer with built-in exposure tool (248nm) is used to perform in situ observations of the decomposition of protective groups (deprotection reactions) in chemically amplified resists during exposure, with the exposure ambient temperature varied. In addition, the activation energy and the prefactor of deprotection reaction necessary for lithography simulation are determined. Resist polymers used in this experiment are poly(p-hydroxystyrene)(PHS) protected by ethoxyethyl (EOE) or by tert-Butoxycarbonyl (t-BOC), and its copolymers. The activation energy is compared at room temperature (23 degree(s)C). As a result, the activation energy for EOE deprotection reaction is 8.90 kcal/mol, while for t- BOC deprotection reaction is 23.65 kcal/mol. The activation energy for EOE resist is much lower than for t-BOC resist. Progress of the deprotection reaction in EOE resist during exposure at room temperature can be explained in terms of differences in activation energies. In the copolymer resist, introduction of EOE into PHS protected by t-BOC resulted in a decrease in the activation energy required for the t-BOC deprotection reaction. Form this it is found that in a resist composed of PHS copolymer with heterogeneous protection groups attached, the interaction affect between protection groups deprotection reactions. Lithography simulations of resist profiles are performed with the activation energy and the prefactor varied, and the effect of the activation energy on the resist profile is investigated. The results indicate that patterning is possible for an exposure ambient temperature of 20 degree(s)C or higher for EOE resist, and that of 70 degree(s)C or higher for t- BOC resist.

Paper Details

Date Published: 24 August 2001
PDF: 12 pages
Proc. SPIE 4345, Advances in Resist Technology and Processing XVIII, (24 August 2001); doi: 10.1117/12.436825
Show Author Affiliations
Yasuhiro Miyake, Litho Tech Japan Corp (Japan)
Mariko Isono, Litho Tech Japan Corp. (Japan)
Atsushi Sekiguchi, Litho Tech Japan Corp. (Japan)

Published in SPIE Proceedings Vol. 4345:
Advances in Resist Technology and Processing XVIII
Francis M. Houlihan, Editor(s)

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